GitLab Create a Feature Branch from the Default Branch

arazzo: 1.0.1
info:
  title: GitLab Create a Feature Branch from the Default Branch
  summary: Resolve the default branch tip and cut a new feature branch from it.
  description: >-
    A foundational GitLab repository flow. The workflow reads the project's
    branch list to discover the default branch and its latest commit, then
    creates a new branch pointed at that same ref so feature work starts from a
    known-good base. Every step spells out its request inline so the flow can be
    read and executed without opening the underlying OpenAPI description.
  version: 1.0.0
  x-realizes-capability-ids:
  - BC-4200.40
  x-capability-derivation:
    method: 'deterministic join: sourceDescriptions -> per-tag OpenAPI -> tag/capability edge. No classification at this step.'
    min_confidence: 0.7
    sources:
    - capability_id: BC-4200.40
      capability_name: Software Construction Management
      spec: gitlab-projects-api-openapi.yml
      confidence: 0.8
    model: Turbo EA Capabilities by Vincent Verdet — Turbo EA, https://github.com/vincentmakes/turbo-ea-capabilities, CC BY 4.0
sourceDescriptions:
- name: projectsApi
  url: ../openapi/gitlab-projects-api-openapi.yml
  type: openapi
workflows:
- workflowId: create-branch-from-default
  summary: Create a new branch in a project from the default branch ref.
  description: >-
    Lists the project's repository branches to find the default branch, then
    creates a new branch that references the default branch so the new branch
    inherits the latest commit.
  inputs:
    type: object
    required:
    - privateToken
    - projectId
    - newBranch
    properties:
      privateToken:
        type: string
        description: GitLab Private-Token used to authenticate the API calls.
      projectId:
        type: string
        description: The ID or URL-encoded path of the project.
      newBranch:
        type: string
        description: The name of the new branch to create (e.g. feature/login).
      ref:
        type: string
        description: Optional ref to branch from; defaults to the default branch name.
        default: main
  steps:
  - stepId: listBranches
    description: >-
      List the repository branches so the default branch and its current commit
      can be identified before branching.
    operationId: getApiV4ProjectsIdRepositoryBranches
    parameters:
    - name: Private-Token
      in: header
      value: $inputs.privateToken
    - name: id
      in: path
      value: $inputs.projectId
    - name: per_page
      in: query
      value: 100
    successCriteria:
    - condition: $statusCode == 200
    outputs:
      defaultBranchName: $response.body#/0/name
      defaultBranchCommit: $response.body#/0/commit/id
  - stepId: createBranch
    description: >-
      Create the new branch referencing the supplied ref (defaulting to the
      project default branch) so it starts from the latest commit.
    operationId: postApiV4ProjectsIdRepositoryBranches
    parameters:
    - name: Private-Token
      in: header
      value: $inputs.privateToken
    - name: id
      in: path
      value: $inputs.projectId
    - name: branch
      in: query
      value: $inputs.newBranch
    - name: ref
      in: query
      value: $inputs.ref
    successCriteria:
    - condition: $statusCode == 201
    outputs:
      branchName: $response.body#/name
      branchWebUrl: $response.body#/web_url
      merged: $response.body#/merged
  outputs:
    createdBranch: $steps.createBranch.outputs.branchName
    createdBranchUrl: $steps.createBranch.outputs.branchWebUrl